Residue algebra is roughly defined as the algebra whose elements are numbers represented by m times some modulus plus a residue. For example, 17 = 4 .times. 4 + 1 which means that the residue of 17 is 1 base 4. Residue algebra may be quite useful in the future in that it allows for a great deal of parallel processing in computations. Numbers are entered into a calculator, encoded by assigning its residue relative to n relatively prime bases, operated upon and then decoded. Encoding and operating are relatively simple operations. However, there are substantial problems with automatic decoding.